Pressure casting machine link mechanism



Jan. 26, 1943. N. LESTER PRESSURE CASTING MACHINE LINK MECHANISM Filed Oct. 4, 1959- 2 Sheets- Sheet l INVENTOR.

NATHAN LESTER. BY (M, 116

E m To N. LESTER PRESSURE CASTING MACHINE LINK MECHANISM Jab. 26, 1943.

Filed Oct. 4, 1959 2 Sheets-Sheet 2' R O vR E T 8 ma L N A H T. m h

$0M 9 ATTORN 5.

Patented Jan. 26, 1943' UNITED STATES PATENTJIIOFFICE.

ranssoan t r a omna mm:

Nathan Lester, Cleveland, om, assignor to The Engineering Company, Cleveland, Ohio,

Lester a corporation of Ohio Application October 4, 1939, Serial No. 297.916

3 Claims.

The present invention relates to a new and improved mechanism for imparting opening and closing movement to the die plates of apre'ssure casting machine. In such a machine, the die plates carry the mold members or die blocks in which the mold cavity is formed when such die plates are in closed position, and into which cavity the material to be cast is forced under casting machine to closed position. The die,

plates are moved to open position in order to permit ejection of the resultant casting. Where both relatively deep or elongated castings are to be made, as well as where it is desired to have an increased working space between the die plates, the amount of movement heretofore obtainable through toggle link mechanism has been found to be necessarily limited.

n the other hand,, where large opening and closing movement between the die plates has been desired, the toggle link mechanism has been eliminatedand the die plates moved by direct connection to a hydraulic ram. However, in order to secure adequate die-closing pressure, the latter type or device must be made extremely large and cumbersome, as well as requiring much more extensive and expensive auxiliary apparatus in the way of pressure pumps, supply lines and pressure fluid reservoirs.

It is the general object and nature of my present invention to provide mechanism for imparting opening andclosing movement to the die plates of a pressure casting machine, which only during the very portion of die plate movement wherein it is best suited and desired. For the remainder of-the movement of the die plate. the toggle link mechanism moves bodily with the prime moving element, 1. e., the. hydraulic piston, so that the movement of the latter is transmitted-directly to the movement of the die plate.

Additional objects and advantages of my invention shall become apparent as the following description proceeds. I

To the accomplishment of the foregoing and related ends, said invention, then consists of the means hereinafter fully described and particularly pointed out in the claims. 15"

The annexed drawing and the following description set forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but oneof various mechanical forms in which the :principle of the invention may be used.

In said annexed drawings: i Fig. l is a longitudinal, vertical sectional view taken through that portion of a pressure cast- I ing machine to which the present invention relates, and showing the die plate and its attached moving mechanism, in closed position; Fig. 2

is a view similar to Fig. 1 but showing the parts L in partially opened position; Fig. 3 is another parts in fully open position; and Fig. 4 is a horiline 4-4 of Fig. 2.

Now referring more' particularly to the drawings there is shown therein the bed-plate or base framel of a pressure casting machine upon which the horizontal tie beam 2 is mounted in comprises a novel combination of both a toggle spaced relationship and by means of the ver- 7 tical, stationary end plate I and the end framework Q. The fixed die plate 5 is mounted between the bfase frame I and beam 2. The movable die plate 8 is adapted to move back and forth in the space between the base I and beam 2, being guided upon tie bars, such as indicated at l. The frame members L1, 3 and 4 thus "constitute aflxed frame structure in which the die plate 5 is stationarily mounted and in which the die plate 6 is movably mounted.

The die plates 5 and 6 are adapted to support die blocks, such as indicated'at 8 and 9, respectively, and in which the mold cavity is formed. A screw jack l9 adjustably mounts the die plate 6 with respect to its carriage plate H, in order to provide for preliminary adjustments in the space between the die plates 5 and ii.

A pair of links I! are pivotally connected by means of the pivot pins 13 to the rear or lefthand face of the carriage plate ii. The links l2. in turn, are pivotally connected by means of the pivot pins l4 to the second pair of links I, and the latter are pivotally connected by means of the pins II to the end of the piston rod ll.

The piston rod I I. carries the piston i3 which reeiprocates within the fixed hydraulic cylinder is mounted on the end of the frame member '4.

The forward or rlghthand end of the links l2 have arcuate bosses or segments 23 which are adapted to fit complementary, arcuate bearing surfaces on the carriage plate ll. Hardened metal inserts 2| and 22 are mounted in the lastnamed arcuate bearing. surfaces respectively, and are adapted to be in alignment and bear against each other'when the links l2 are in closed position, such as shown in Fig. l.

Abutments or shoulders are provided uponthe links l2 at points closely adjacent the pivot pins i4. These abutments are in the form of hardened metal inserts 23 which are adapted to bear against other hardened metal abutments 24 carried in the frame member 4. The abutting surfaces of the members 23 and 24 are inclined at an acute angle, as indicated by the line a. to the normal to the direction of traverse of the die plate 6, and thus, constitutewedges or wedge surfaces, which, when slid one over the other, will impart a wedging action to the longitudinal movement of the links l2 and its connected plates II and l.

Slide-ways or slide bearing surfaces 26 are mounted in the frame member 4 adjacent the abutments 24 and disposed in a position parallel to the direction of movement of the die plate 8 and of the piston rod ll. These bearing surfaces 28 are adapted to make sliding engagement with bearing surfaces 21 on the intermediate portion of the links l2.

Laterally projecting legs 23 extend inwardly from the sides of the links l2 and are adapted to contact each other in end-abutting relationship and to thus limit the collapsing movement of the links l2 and I5. Referring to Figs. 1 and 2, it will be seen that the links l2 have a pivotal movement from the two extremes shown in the respective figures. This amount of pivotal movement is exemplified by the longitudinal center lines b and 0, respectively, shown in Fig. 2. The distance (1 represents the chord of the arc of pivotal movement of the links 12 at the surface of the abutment 23. The rlghthand end of the links I2 is offset laterally so that the center of the pivot pin I3 is correspondingly offset a distance d from the center line b of the links l2. Thus, the links l2 are adapted to occupy a position at the inward extreme of their pivotal movement, where their longitudinal bearing surfaces will be parallel to the direction of traverse of the die plate 6 and adapted to make surface to surface contact with the bearing surfaces 26.

From the foregoing description, the opera-.

with the bearing surfaces 26 on the framememher 4, they cannot move outwardly but will slide along longitudinally until the parts approach closed positlonof the die plates, as shown in Fig. 2. At this point, the links l2 are freed for outward pivotal movement and the free pivots I4 also undergo pivotal movement whereby a toggle action is effected to force the wedge surface abutments 23 and 24 in contact, and thereby, to press the die plates 5 and 3 with their respective die blocks 3 and I into tightly'closed relationship. as shown in Fig. 1.

Upon return or opening movement of the die plates, the piston rod I1 is moved in a lefthand direction, which, in turn, operates to effect a collapsing movement of the toggle links l2 and II until the projecting legs 23 abut against each other and thereby limit such movement. At this point, the links l2 will then be in a position so that the abutment 23 clears the abutment 24 'andthelinks l2 and liwillthenbeinarigid position, with their pivotal movement immobilized so that they will move bodily along with the piston rod and the plates II and 6 to produce a quick-acting opening movement of die plates.

The links l2 and ii are thus joined in a pivot, at the pin l4, which is non-connected to any other link mechanism element which might determine its path of travel: such pivot, therefore, being a free pivot, the movement of which is controlled indirectly by the movement permitted to the links l2. the maximum mechanical advantage incident to toggle link action is obtainedwhen the links I! reach a position of longitudinal alignment, i. e.,

when the centers-of the pins l4 and I6 are in a straight line. Thus, the toggle link mechanism approaches and reaches "dead center" position as the wedge surfaces of the abutments 23 and 24 are in contact.

The superior mechanical advantage obtained through the combined action of the toggle link mechanism and of the wedge surfaces of the abutments 23 and 24 is operative only during that portion of the stroke of the die plate movement where it is most suited and required. Such portion of the stroke is indicated by the distance e in Fig. l. The remainder of the opening and closing stroke or movement of the die plate 3 is produced directly by movement of the piston rod l1.

In this manner, relatively rapid opening and closing movement of the die'plates, as well as a relatively large amount of such movement is obtained. At the same time, the very high force or pressure required for holding the die plates in closed position is not sacrificed.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means may be employed.

I, therefore, particularly point out and distinctly claim as my invention:

1. A pressure casting machine link mechanism comprising a fixed frame member, a die plate movable thereon, a' pressure cylinder, piston and piston rod so mounted on said frame member as to move said piston rod in a direction parallel to that of said die plate, dual link members each pivotally connected at one end to said die plate. other dual link members each pivotally pinned at one end to said piston rod, the other ends of each of said dual link members being connected to each other at a free pivot, and complementary straight, angular wedge surfaces on said firstnamed dual link members and on said frame member respectively, said wedge surfaces being It will also benoted that adapted to contact each other and to impart wedge action movement to said die plate during movement of said free pivot, said wedge surfaces 1 on said link members forming a bodily part thereof, said other dual link members being in alinement when said complementary. wedge surfaces are fully engaged.

2. A pressure casting machine link mechanism comprising a fixed frame member, a die plate movable thereon, a pressure cylinder, piston and piston rod so mounted on said frame member as to move said piston rod in a direction parallelto that of said die plate, dual link members each pivotally connected at one end to said die plate, other dual link members each pivotally pinned at one end to said piston rod, the other ends of each of said dual link members being connected to each other at a free pivot, complementary straightangular wedge surfaces on said firstnamed dual link members and on said frame member respectively, said wedge surfaces being adapted to contact each other and to impart comprising a fixed frame member, a die plate movable thereon, a pressure cylinder, piston and piston rod so mounted on said frame member I as to move said piston rod in a direction parallel wedge action movement to said die plate during movement of said free pivot, and laterally extending projections on each of said first-named dual link members, said projections being adapted to abut each other when said wedge surfaces are moved out of contact, said other dual link members being in alinement when said complementary wedge surfaces are fully engaged.

3. A pressure casting machine link mechanism to that of said die plate, dual link members each pivotally connected at one end to said die plate.

other dual link members each pivotally pinnedat one end to said piston rod, the other ends of each of said dual link members being connected to each other at a free pivot, complementary straight, angular wedge surfaces on said firstnamed dual link members and on said frame member respectively, said wedge surfaces being adapted to contact each other and .to impart wedge action movement to said die plate during movement of said free pivot, laterally extending projections on each of said first-named duallink members, said projections being adapted to abut each other when said wedge surfaces are moved out of contact, and slide bearing surfaces on said frame member parallel to said piston rod and adapted to contact with each of said first-named dual link members during longitudinal pivotal movement of the latter, said bearing surfaces terminating at said wedge surfaces on said frame member whereby said dual link members are freed for pivotal movement towards contacting engagement of said wedge surfaces. said other dual link members being in alinement when'said complementary wedge surfaces are fully engaged.

NATHAN LESTER. 

